Emergency eyewashes and showers are used in a variety of industrial, educational, and governmental settings in which dangerous chemicals are present. Should a user's eyes become contaminated (or the user's body become contaminated) a nearby, easy to use, and safe emergency washing system can provide quick and thorough flushing of the contamination.
However, some emergency wash systems may not be completely safe to use. Some systems are provided with pressurized water from a plumbing system in which the washing system is placed at a “dead end” of the plumbing, meaning that the emergency wash system provides the only exit for water within the dead ended plumbing. Since emergency washing systems are not used often, the water in the building plumbing is stagnant. Any contaminants that find their way into this plumbing (such as by leakage past seals, corrosion, or other ways) will remain in the dead end plumbing leg. If this contaminated feed water is not removed, then it may be applied to flush other contamination off of a user, even though the water is not safe for such flushing, and further showers the user with yet other contaminants.
Further yet, some emergency washing systems are configured to provide tepid water to the emergency washing system. This tepid water is often produced in a thermostatically controlled mixing valve, in which the mixing valve is provided with water from the building plumbing to a valve cold inlet, and in which water from the building plumbing is further provided to a water heater. Heated water is also provided to the mixing valve, which then provides a controlled mixing of cold and hot flow streams to achieve a tepid temperature.
However, a problem arises if the thermostatic mixing valve is provided with water having a high mineral content. These minerals may precipitate and coat various surfaces within the mixing valve. These coatings can cause improper operation of the mixing valve, including seepage of hot water provided by the water heater in a reverse direction into the source water of the dead end leg connected to the mixing valve cold inlet. In such cases, it is possible that the seepage is consistent enough to slightly increase the temperature within the dead end leg of the building plumbing.
The presence of this slight elevation in temperature in a dead ended plumbing leg can result in potentially dangerous contamination. It is possible that some dead ended plumbing legs may include the bacterium Legionella in some parts of a building's water system. The presence of Legionella bacteria may not by itself result in Legionnaires' disease (LD). LD is contracted by the user aspirating the colonized water into the user's lungs. Unfortunately, the use of spraying nozzles on an emergency eye wash system can increase the danger of transmitting the bacteria. In the case of an emergency eye wash system as discussed above, the warm water temperature in the dead end leg promotes the growth of Legionella. 
One manner of removing the contaminated water from the dead ended leg is to periodically flush the system. However, currently used flushing techniques have shown to be ineffective in thoroughly flushing the dead ended leg. It appears that this ineffectiveness is a result of at least three factors: (1) building plumbing systems typically use large diameter pipe capable of providing high flow rates over long distances, which results in a large internal volume of dead ended water; (2) some emergency eye systems are designed to provide only modest water flow (such as 3-5 gallons per minute); and (3) the technician that is tasked with periodically flushing the dead ended leg often simply turns on the emergency wash system for a longer than usual period. However, the period of flushing (3) is typically not long enough at the low flow rate (2) to fully purge the large, internal dead space (1). Therefore, the typical flush of an emergency wash system does not re-establish a safe water supply in the dead end let.
Yet another factor that complicates the problems thus discussed is the desire to use less water in any new water-handling device. Emergency wash systems can benefit from lower flow rates by producing a gentler and more predictable upward stream of water to flush the user's eyes or face. If an emergency washing system is not comfortable, then it is less likely to be used, which defeats the purpose of the emergency wash system. It has been observed that some eye washing systems produce output sprays that are too strong or flow too high to be comfortably used.
This variation in the emergency spray may require the complexity of a separate, manually adjustable flow valve, along with the expense of the labor necessary to set the adjustment properly. Achieving a proper and comfortable spray pattern can be a problem when considering the wide range of water pressures that exist in a building plumbing system. The pressure of the leg of the plumbing system that provides the emergency wash may range from very low to very high values, depending upon the size of the pipes, the age and material buildup within the pipes, whether or not other devices are provided with water from the same leg, or the unpredictable, on and off nature of other devices receiving water from the same plumbing leg.
Yet another problem with many emergency washing systems is their susceptibility to breakage during maintenance and usage. Many current eye washing systems have one rigid pipe that provides water to the washing system, and a second rigid pipe that takes away the water drained from the emergency system. These two rigid pipes are typically used for supporting the collection basin of an emergency eye wash system. However, it has been found that some systems are installed with rigid pipes that are of inadequate strength to support the wash basin, especially when a maintenance technician needs to perform maintenance (such as flushing), and must apply excessive loads to the emergency wash system in order to disassemble it. Still further, these rigid pipes are typically coupled to the basin, plumbing, or shut off valve, etc., with pipe connections that, although leak tight, are unable to resist a torque applied to the wash system during disassembly—the joints simply slip. Yet further damage to an emergency washing system can arise when the user, who is typically in a hurry and distracted, bears his weight against the wash basin. The rigid pipes and slipping connections may not be strong enough to support the user's weight. Current emergency washing systems often do not include any structure that is capable of supporting the high maintenance loads or the user's weight. Attaching the basin to a wall or providing a separate floor stand presents still further problems. A connection from a wall to the basin is spatially independent of the basin plumbing, but it is often a bad design practice to try to positively locate one item (the drain basin) to two different objects (the wall vs. the plumbing system). A problem with a separate vertical stand for the drain basin can be a lack of available floor space. Especially in industrial settings, floor space is highly prized. An emergency wash system that does not contact the floor is therefore more shop-friendly than a system that requires its own stand, and therefore more likely to be placed in more locations within an industrial facility. Thus improves the overall efficacy of providing emergency washing to contaminated users.
Yet another aspect of a low flow emergency system according to some embodiments of the present invention is to provide tepid water by means of a thermostatically controlled cartridge valve that is adapted and configured to shut off the flow of how water if there is a failure of the thermostat. It has been found that an emergency washing system adapted and configured to provide a low flow rate of tepid water can be susceptible to variations as to overall low delivery pressures, as well as relative differences in pressure between the hot and cold inlets. It has been found that utilizing a thermostatically controlled valve assembly adapted and configured to provide a positive shut off in the event of a thermostat failure also provides improved operation of a low flow system.
What is needed are improvements that address one or more of the aforementioned problems. Various embodiments of the present invention provides such novel and nonobvious solutions.